Adventures with AIRS: continued Tim P. Barnett David W. Pierce Eric Fetzer Andrew Gettleman Amy Braverman Sam Iacobellis
Outline/Summary • Water Vapor: AIRS vs. Climate Models (models wrong AND error is important) . Cloud Issues (what a mess…HELP!) . Moisture Flares (promising opportunities for AIRS? )
Annual mean specific humidity: models systematically differ from AIRS
Fractional difference 50-100% at 500 hPa
Fractional differences: greater with height
Seasonal variability: AIRS vs. AR4 models Red: Specific humidity from AIRS. Whiskerplots: 5, 25, 50, 75, and 95 percentiles of AR4 models
Temperature (K) in AIRS compared to AR4 models, 400 hPa
Temperature (K) in AIRS compared to AR4 models, zonal average
Relative humidity in AIRS compared to AR4 models, 400 hPa (Andrew Gettleman’s RH) Note: Values are percentages, i.e., (model-AIRS)/AIRS*100. Using Andew Gettleman RH vals, not AIRS
PDF of specific humidity error
PDF of specific humidity error
WHO CARES? • Is ‘q’ error important? • If so, how important? • Modeling community disinterest? • SCM work
Forcing error, Single Column Model (upper troposphere) SCM delta-OLR @ TOA
Cloud issues Compare: AIRS fractional clouds vs. CGCM fractional clouds
Cloud fraction DJF climatology AIRS vs. AR4 models Cloud fraction, 0 to 100%
Cloud fraction DJF climatology AIRS vs. ISCCP
ISCCP anomalies vs. AIRS ISCCP (removed mean = 67%) Pattern Correlation=0.85 AIRS (removed mean = 42%)
Moisture flares • Associated with heavy rain events • Predictive skill • Physics=? • AIRS might give us their third dimension and insight into how they work
Moisture flare: el Nino event
SoCAL moisture flare composite: el Nino
Vertical structure of the Dec 25-29, 2004 moisture flare (contour taken along the black line) Relative humidity from A. Gettleman
Conclusions • ‘q’ and ‘RH’ errors are real and large • Radiatively large w.r.t GHG forcing • Clouds: Expert help required but promising • AIRS can help understand moisture flare structure and, maybe, physics • ASIDE: Quality flag adventures (for beginners)
Absolute differences: central latitudes near surface
PNW la Nina rain event (moisture field)
Other Southwestern U.S. Moisture flares Total cloud liquid water from AIRS; interpolated across missing values
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